煤层注水防突最优润湿时间试验研究

Experimental study on the optimal wetting time of coal seam water infusion for gas outburst prevention

煤层注水就是通过钻孔将压力水注入煤体,使煤、瓦斯和水之间产生复杂的三相耦合作用,以降低煤炭开采时煤尘生成量并防止煤与瓦斯突出。煤矿采用煤层注水防突措施后,何时进行采掘作业,长期以来缺少可靠的判断方法。针对此问题,在实验室通过测定煤层注水后不同润湿时间下预先吸附瓦斯煤样的解吸速度,根据煤、水充分润湿后水与煤体中孔隙的毛细作用和抑制瓦斯解吸效应最强原理,以第一分钟瓦斯解吸速度V_(1)及解吸速度衰减系数kt作为研究指标,在特定试验条件下,计算得到超化、古汉山和寺河等煤矿煤样的最优润湿时间,分别为6.44,7.00,10.41 h。最后,结合各煤样的注水相关参数,论证证明最优润湿时间确定方法是可行的,该方法对煤层注水防突技术参数优化具有重要的指导意义。

Coal seam water infusion is a technical measure to inject pressure water into coal body through boreholes, which results in a complex three-phase coupling among coal, gas and water, and a reduction of coal dust generation and an effect of coal and gasoutburst prevention.However, there is lack of a reliable method to evaluate the optimal wetting time after coal seam water infusion for a long time.In order to solve this technical problem, the desorption rate curves of pre-adsorption gas coal samples were tested in different wetting times after water injection.According to the principles that both the capillary function and the inhibitory effect of gas desorption was strongest after coal being fully wetted, with the first minute gas desorption rate V_(1) and gas desorption attenuation coefficient kt as the research indexes, the optimal wetting times of Chaohua(CH),Guhanshan(GHS)and Sihe(SH)coal samples were determined, which were 6.44,7.00,10.41 h, respectively.Finally, combining the characteristics of coal samples and the contact angle with water, the feasibility of this method of the optimal wetting time was verified, which was of great guiding significance to the optimization of the technical parameters of coal seam water infusin for gas outburst prevention.